A sonar image of the Akagi, sunk at Midway in 1942. Photos: Vulcan, Inc.

They were thought to have been lost in the watery depths of the vast Pacific Ocean. But now, explorers have found two Japanese aircraft carriers sunk in battle during World War Two.

The carriers were among seven ships that went down during the Battle of Midway in June 1942, a decisive victory for the United States against Japan in the Pacific Theatre.

On 16 October 2019, one ship, the Kaga, was discovered after an intensive search. Just a couple of days later, the wreckage of the Akagi was also found.

The Kaga is the first sunken Japanese aircraft carrier ever to be discovered. Up until now, only one other ship sunk in the Battle of Midway, the American USS Yorktown, had been located. It was found in 1998.

An image of the gun mount on the Kaga. Photo: Vulcan, Inc.

The astonishing discoveries were made by the research vessel Petrel, owned and operated by Vulcan Inc, a company established by the late Microsoft co-founder Paul Allen. Using an autonomous underwater vehicle (AUV) fitted with sonar, the wrecks were located deep below the surface.

The Kaga rests at 5,400 metres underwater, while the Akagi rests at 1,600 metres. Both are in the Central Pacific in the Papahanaumokuakea Marine National Monument, of which Vulcan documented more than 500 square miles over several weeks.

In the Battle of Midway, six months after Japan’s December 1941 attack on Pearl Harbor, the Japanese Navy hoped to inflict a final defeat on the US fleet by luring them into an ambush.

Yet thanks to code breaking, the plan was uncovered, and the US prepared its own ambush. Surprising the enemy as they approached Midway, the US inflicted devastating damage on the Japanese and changed the course of the war.

The Akagi two months before the Battle of Midway.

The battle involved four Japanese and three American aircraft carriers. All four of the Japanese carriers – Kaga, Akagi, Soryu, and Hiryu – also involved in Pearl Harbor, were sunk. The US lost carrier Yorktown and destroyer Hammann. Commenting on the discovery, Robert Kraft, director of sub-sea operations for Vulcan Inc, said:

This project is significantly different from previous missions as it required a level of investigation, analysis, and survey of a carrier-based engagement initially separated by over 150 nautical miles.

He added:

It was a major carrier-to-carrier battle that left its eerie evidence strewn for a total area covering thousands of square nautical miles across the ocean floor. With each piece of debris and each ship we discover and identify, our intent is to honour history and those who served and paid the ultimate sacrifice for their countries.

Petrel is a 250-foot research vessel which, due to its advanced underwater equipment, is one of the few ships on the planet capable of exploring depths of up to 1,800 metres.

Its crew has discovered over 30 sunken warships, including USS Hornet, USS Wasp, and, most famously, USS Indianapolis. Additional expeditions have resulted in the discovery of the Japanese battleship Musashi and the Italian WWII destroyer Artigliere.

This article was published in the December 2019 issue of Military History Matters. To find out more about subscribing to the magazine, click here.﻿